Hay fever, also known as allergic rhinitis, is a common condition that shows signs and symptoms similar to a cold with sneezing, congestion, runny nose and sinus pressures.
This article is about allergic rhinitis. You can read about non-allergic rhinitis here.
Hay fever is caused by an allergic response to airborne substances, such as pollen - unlike a cold which is caused by a virus. The time of year in which you get hay fever depends on what airborne substance you are allergic to.
The substance that causes an allergic reaction in hay fever is called an "allergen". For the majority of people, those who do not get hay fever, these substances are not allergens, because their immune system does not react to them.
Despite its name, hay fever does not mean that the person is allergic to hay and has a fever. Hay is hardly ever an allergen, and hay fever does not cause fever.
Although hay fever and allergic rhinitis have the same meaning, most lay people refer to hay fever only when talking about an allergic reaction to pollen or airborne allergens from plants or fungi, and understand allergic rhinitis as an allergy to airborne particles, such as pollen, dust mites or pet dander which affect the nose, and maybe the eyes and sinuses as well.
The rest of this article focuses on hay fever caused by pollen and other airborne allergens that come from plants or fungi. Hay fever caused by pollen is also known as pollinosis.
Some people are only mildly affected by hay fever and rarely reach a point where they decide to seek medical advice. However, for many, symptoms may be so severe and persistent that they are unable to carry out their daily tasks at home, work or at school properly - these people will require treatment. Treatments may not get rid of the symptoms altogether, but they usually help to lessen their impact, making them easier to live with.
As with other allergies, hay fever symptoms are a result of your immune system mistaking a harmless substance as a harmful one, and releasing chemicals that cause the symptoms.
It is estimated that about 20% of people in Western Europe and North America suffer from some degree of hay fever. Although hay fever can start affecting people at any age, it generally develops during childhood or early adulthood. It is said that the majority of hay fever sufferers find their symptoms become less severe as they get older.
Contents of this article:
Fast facts on hay fever
Here are some key points about hay fever. More detail and supporting information is in the main article.
- Allergic rhinitis, often called hay fever, is a common condition that causes symptoms such as sneezing, stuffy nose, runny nose, watery eyes and itching of the nose, eyes or the roof of the mouth.
- Roughly 7.8% of people 18 and over in the US suffer from hay fever.
- Around 17.6 million (7.5%) adults in the US are diagnosed with hay fever per year.
- There are 6.6 million (9%) children diagnosed with hay fever each year in the US.
- A 2010 study suggests that white children are more likely to have hay fever (10%) than black children (7%).
- Allergic rhinitis can be seasonal or perennial. Symptoms of seasonal allergic rhinitis occur in spring, summer and early fall.
- The symptoms of hay fever are usually caused by allergic sensitivity to pollens from trees, grasses or weeds, or to airborne mold spores.
- Allergic rhinitis treatment options are: avoidance, eliminating or decreasing your exposure to the irritants or allergens that trigger your symptoms, medication and immunotherapy.
- Immunotherapy (allergy shots) helps reduce hay fever symptoms in about 85 percent of people with allergic rhinitis.
- Allergic diseases, which include asthma, are the fifth most prevalent chronic diseases in all ages, and the third most common in children.
Symptoms of hay fever
Symptoms of hay fever may start at different times of year, it depends on what substance the patient is allergic to. If a person is allergic to a common pollen, then when the pollen count is higher his symptoms will be more severe.
Common hay fever symptoms include:
- Watery eyes
- Itchy throat
- Itchy nose
- Blocked/runny nose
Severe hay fever symptoms may include:
- Loss of smell and taste
- Facial pain caused by blocked sinuses
- Itchiness spreads from the throat, to the nose and ears
Sometimes hay fever symptoms can lead to:
People with asthma may find that when hay fever symptoms emerge their wheezing and episodes of breathlessness become more severe. A significant number of people only have asthma symptoms when they have hay fever.
What causes hay fever?
Grass pollen tends to affect people in late spring and summer.
Hay fever occurs when the immune system mistakes a harmless airborne substance as a threat. As your body thinks the substance is harmful it produces an antibody called immunoglobulin E to attack it. It then releases the chemical histamine which causes the symptoms.
There are seasonal hay fever triggers which include pollen and spores that will only cause symptoms during certain months of the year.
The following are some examples of hay fever triggers:
- Tree pollen - these tend to affect people in the spring.
- Grass pollen - these tend to affect people later on in the spring and also in the summer.
- Weed pollen - these are more common during autumn (fall).
- Fungi and mold spores - these are more common when the weather is warm.
What are the risk factors for hay fever?
A risk factor is something that increases a person's chances of developing a disease or condition. Below are some risk factors for hay fever:
- Family history (inheritance, genetics) - if you have a close family member who has/had hay fever, your risk of developing it yourself is higher. There is also a slightly higher risk if a close family member has any type of allergy.
- Other allergies - people with other allergies are more likely to suffer from hay fever as well.
- Asthma - a significant number of people with asthma also have hay fever.
- Gender and age - hay fever affects more young males than young females. Before adolescence, twice as many boys as girls have hay fever. However, after adolescence many boys outgrow it and slightly more girls than boys are affected.
- Birth date - people born during the high pollen season have a slightly higher risk of developing hay fever than other people.
- Second-hand smoke - infants and babies who are regularly exposed to cigarette smoke during their first years of life are more likely to develop hay fever than babies who aren't.
- Being the first child - a higher percentage of firstborn children eventually develop hay fever, compared to other people.
- Babies from smaller families - a higher proportion of babies with no siblings, or just one sibling develop hay fever later on compared to babies born to larger families.
- Babies born to high income families - babies born to families with a high standard of living have a higher risk of developing hay fever later on, compared to other babies.
Many experts believe that the last three risk factors are linked to childhood infections. If a baby and/or small child has had fewer infections, there is a greater risk of autoimmune problems.
On the next page we look at how hay fever is diagnosed, tips for minimising the impact of hay fever and the available treatments to help with the condition.